Effects of Influencing Factors on Distribution Behaviors of Vanadium between Hot Metal and FeO‐SiO₂‐MnO (‐TiO₂) Slag System

Abstract

The distribution behavior of vanadium between a hot metal and a FeO‐SiO2‐MnO (‐TiO2) slag system was studied under laboratory conditions, together with the effects of influencing factors such as temperature, slag composition, the ratio of slag to hot metal, and the initial Si and/or Ti content in hot metal. The results suggested that in a ternary FeO‐SiO2‐MnO slag system, with an increase in temperature and an increase in the SiO2 content of slag, the extraction ratio ($\eta _{V} $), distribution ratio of V ($L_{V} $) and the vanadium capacity of the slag ($C_{VO_{3} {}^{3{-} } } $) decreased, while the effect of MnO content in slag showed a different tendency under different situations. For both high and low ratios of slag to hot metal, the extraction ratio of V reached its maximum value under slag compositions of 13%–25% MnO and 10%–24% SiO2, which correspond to the regions with lower melting point and lower viscosity of the slag. In a quaternary FeO‐SiO2‐MnO‐TiO2 slag system,$\eta _{V} $,$L_{V} $, and $C_{VO_{3} {}^{3{-} } } $ decreased, while the activity coefficient of V2O3 increased, as the TiO2 content increased. Further, the data suggested that under laboratory conditions the effects of influencing factors on the extraction ratio of V from hot metal decreased in the following order: final slag composition > temperature > initial Si and/or Ti content in hot metal.

Vanadium Extraction from a Fe–V (2.0 Mass%)–P (0.1 Mass%) Melt and Investigation of the Phase Relations in the Formed FeO–SiO2-Based Slag with 20 Mass% V

“…8 together with the results at 1673 K [9]. The phase fraction of SP is derived according to the following equation: [16]. Solids have in general much higher impact on viscosity than minor alteration of, for instance, the slag composition [21].…”

“…In the present study, the effect of temperature on the phase fraction of SP in the solid-liquid mixture is negligible in the temperature range of 1573-1773 K. The temperatures within this range could therefore be expected to have a relatively small impact on the slag fluidity and thereby the V extraction. The hot metal temperature at tap should therefore be targeted to maximum 1673 K as it is also well known that C retention is promoted by low process temperature [16,22]. C retention is important from the perspective of upholding a low liquidus temperature of the metal [23], lower consumption of solid coolants in the V-extraction process, and higher scrap ratio when/if converted to steel in a second converter.…”

“…The distribution coefficient for V (L V ) has been determined in a number of experimental studies [16][17][18][24][25][26]. The studies by Inoue et al [24] and Selin [25,26] were performed for MgO-saturated slags and thus outside the normal production range for V slag.…”

“…The study by Howard et al [18] was performed at 1873 K which is considerably higher than the scope of the present study. Werme [17] investigated the effect of L v with the addition of oxides like CaO, Na 2 O, MgO, Al 2 O 3 , and TiO 2 at 1573 K. Zhang et al studied the influencing factors, such as temperature, slag composition, and slag-to-metal ratio on L v between hot metal and FeO-SiO 2 -MnO (-TiO 2 ) slag [16]. The L v dependencies on SiO 2 and temperature obtained in the present study are shown in Fig.…”

“…The V slags were found to be solid-liquid mixtures, either in a two-phase region consisting of a liquid and a solid spinel phase, or in threephase region consisting of liquid, spinel phase, and free silica. Spinel and/or karelianite precipitation in V-saturated slags [10][11][12][13][14][15] results in a sharp increase of the slag viscosity [14], which has been reported to have an impact on the extraction efficiency of V [16]. Studies on phase relationships of V slags will render a fundamental foundation toward the development of a V-extraction method from hot metal highly enriched in V.…”